1. Field of the Invention
The present invention relates in general to a steering wheel assembly for vehicles, and more particularly to an energy absorbing steering wheel assembly which is capable of minimizing damages to a driver in case of an accident and possible impact between the steering wheel and the driver's body.
2. Description of the Prior Art
Japanese Utility Model First Provisional Publication 61-103276 discloses an energy absorbing steering wheel assembly. This steering assembly comprises a cylindrical energy absorbing member which is installed between an upper mounting plate secured to a covering pad and a lower mounting plate connected to a hub receiving therein an end portion of a steering shaft. The covering pad is positioned at a general center of an annular rim and connected to the rim through a plurality of spokes extending radially outwardly therefrom. The covering pad conceals the cylindrical member so as to improve an external appearance of the steering wheel. The cylindrical member is received at its top portion in a rectangular opening of the upper mounting plate and at its bottom portion in a rectangular opening of the lower mounting plate. The cylindrical member is secured to the upper and lower mounting plates by welding or the like.
When, due to a vehicle collision or the like, the body of a driver collides against the covering pad of the steering wheel, impact energy is dissipated by deformation of the cylindrical member. In case that impact energy is applied to the covering pad along the axis of the steering shaft, the cylindrical member is compressively deformed in a controlled manner so as to dissipate impact energy satisfactorily.
However, in case that impact energy is applied to the covering pad at an angle to the axis of the steering shaft, the upper mounting plate and the cylindrical member tend to be displaced relative to each other and to the lower mounting plate. With this, a desired load-deformation characteristic may not be obtained so that impact energy may not be dissipated satisfactorily.